Gaming Google is an old sport. Long ago we had a company here give free hosting for small sites. The catch was the their server inserted porn links when Google Bot visited the page. So many people were merrily creating their subdomains while secretly helping the porn rankings. It was infuriating and amazing at the same time.
Do you have more details? The twist of only serving the inserted links to the Google Bot but not to normal users makes sense, but isn't an approach I've seen before.
I didn't look into it very much back then. They were giving free hosting and subdomains back when such a thing was expensive and jumped on it for my homepage. Somehow I saw the Google cache of my page and it was surrounded by ads.
So they were serving different content to different clients based on user agent and/or IP block.
When I found out I deleted my account.
I see the site still exists, they might do the same thing. It's 3x on the .ro TLD.
